His first goal came from the very edge of Vancouver's box, when the veteran forward worked himself into an open pocket of space and finished with a left-footed shot over Whitecaps goalkeeper Stefan Marinovic.

The second, which came with Seattle still vulnerable to an away goal that would have knocked it out, was assisted by both Nicolas Lodeiro and Victor Rodriguez as Dempsey snuck in at the back post to put the game away..

"The first goal was a really good effort from distance," Schmetzer said. "The second goal was just his instincts inside the box.

"It was a good play from Nico and Victor to get the ball back in quickly, even though some of us might have been saying to slow it down, but those guys made the plays that they needed to. Clint made the plays that he needed to."

Dempsey missed the first leg of the series due to a red-card suspension he'd picked up on the final day of the regular season. He sat out all of Seattle's MLS Cup run last year due to an irregular heartbeat diagnosis, and asked if he could tell if his leading man was especially raring to go on Thursday, Schmetzer said: "He's been ready for a long time."

Dempsey, however, played down any greater significance to his performance based on his recent postseason absences.

Clint Dempsey celebrates after scoring the opener for Seattle against Vancouver.

"Anytime you can play in playoff games and contribute in good way, it feels good," Dempsey said. "I don't look at like that, like I missed out. I'm just excited to be playing now and want to make the most of the time I have left."

Though the Whitecaps were outshot 20-2 and surrendered the majority of the possession, it appeared as though the visitors might be able to grind their way into extra time with the aggregate score still at 0-0 into the second half. Many of the 39,587 rain-soaked fans in attendance began preparing for a long night.

Then Dempsey delivered -- not just once but twice -- a playoff performance that will not soon be forgotten in Cascadia.

"He's worked hard at his craft for many years, starting when he was a little kid, when his mom and dad took him to all the games and all that sort of stuff," Schmetzer said. "His finishing and his ability to just find goals in moments is tremendous. Ever since he's come here, he's scored some pretty big goals for this club.

"Tonight was one of those textbook nights where he shows up and does what he does best."

Seattle will now face either rival Portland or Houston in the conference finals starting on Nov. 21.

Matt Pentz is a Seattle-based soccer reporter covering primarily the Sounders, Timbers and Whitecaps. Follow him on Twitter @mattpentz.